Gastric Carcinoma Flashcards
Gastric carcinoma
- Intestinal type: inflammatory process that progress from chronic gastritis to atrophic gastritis and finally to intestinal metaplasia and dysplasia
- diffuse type: linitis plastic
Risk factor of gastric carcinoma
- nutritional (high salted meat or fish, high nitrate consumption)
- smoking
- radiation exposure
- past medical history (H.pylori infection, prior gastric surgery, gastritis, gastric atrophy)
- family history of gastric cancer
microscopic types of gastric ca
- adenocarcinoma: arise from columnar cells of gastric glands
- squamous cell carcinoma: arise from terminal part of oesophagus containing squamous epithelium
- adenosquamous
- undifferentiated
- lymphomas
Macroscopic type of gastric ca
- proliferative type
- ulcerative type
- colloid type
- scirrhous type
spread of gastric ca
- direct: penetrate muscularis, mucosa and then to adjacent organs (pancreas, spleen)
- lymphatics: celiac node, left supraclavicular lymph node (Troisier’s sign)
- bloodstream: liver, lung, bone, brain
- transcoelomic implantation: Krukenberg tumour, ascites, umbilicus nodules (Sister Mary Jospeh’s nodule)
Lauren classification
Intestinal type
- environmental cause
- RF: gastric atrophy, intestinal metaplasia
- men> women
- increasing incidence with age
- gland formation
- hematogenous spread
- microsatellite instability, APC gene mutations
- resembles carcinoma in tubular GIT and form polypoid tumour or ulcer
Diffuse type
- familial
- more common in blood group A
- women> men
- younger age group
- poorly differentiated signet ring cells
- transmural/ lymphatic spread
- decreased E-cadherins
- infiltrate deeply into stomach without forming obvious mass lesion, spread widely in gastric wall
- worse prognosis
Japanese classification (early)
defined as invasive gastric cancer that invades no more deeply than submucosa, irrespective of lymph node metastasis (T1, any N)
- Type I: polypoid
- Type IIa: elevated
- Type IIb: flat
- Type IIc: depressed
- Type III: excavated
Borrmann classification (advanced)
advanced gastric cancer involves muscularis layer
- Type I: polypoid
- Type II: fungating
- Type III: ulcerated
- Type IV: diffusely infiltrative
TNM staging
T0: no evidence of primary tumour
Tis: carcinoma in situ
T1: tumour invades lamina propria or submucosa
T2: tumour invades muscularis propria
T3: tumour invades subserosa
T4: tumour invades serosa and adjacent structures
N0: no regional lymph node metastasis
N1: metastasis in 1-2 regional lymph nodes
N2: metastasis in 3-6 regional lymph nodes
N3: metastasis in 7 or more regional lymph nodes
M0: no metastasis spread to distant organs
M1: distant metastasis
clinical features of gastric ca
- onset of indigestion or epigastric pain is vague
- loss of appetite
- loss of weight
- tumour near cardia — obstruction of oesophagogastric junction — dysphagia
- tumour in pyloric region — obstruct outflow of food from stomach — vomit large amount of undigested food and notice epigastric discomfort and distension
- metastasis: weakness, tiredness or dyspnoea
PE of gastric ca
General appearance
- cachexic (wasting of temporal bone, hypothenar muscle, interosseous muscle)
- pallor (chronic bleeding and lack of iron in diet — iron deficiency anaemia)
- metastasis: multiple hepatic metastases (mild jaundice) or metastases in lymph glands around porta hepatis
Neck
- palpable supraclavicular gland (Virchow’s gland): Troisier’s sign
- left axillary (Irish node)
Lung
- pulmonary metastases: pleural effusion
Lower limbs
- oedema (venous thrombosis, hypoalbuminaemia)
abdominal examination of gastric ca
Inspection
- abdomen is often scaphoid (weight loss)
- generalized abdominal distension (ascites)
- epigastric distension and visible peristalsis (pyloric obstruction)
Palpation
- epigastric tenderness
- deep palpation on full inspiration: epigastric mass (hard, irregular, dull)
- liver may be palpable and its edge and surface knobbly and irregular
- epigastrium distended
- pyloric obstruction: succussion splash
Percussion
- shifting dullness (ascites)
Auscultation
- bowel sounds normal
Rectal examination
- metastatic nodules may be felt in pelvis and ovaries (Krukenberg’s tumour)
- metastatic nodules may be felt in rectovesical pouch (Bloomer’s shelf)
- melenic stool
Diagnostic of gastric ca
flexible upper OGDS with biopsy
- benign gastric ulcer: convergence of mucosal fold toward ulcer, punched out due to acid digestion, peristalsis seen around ulcer
- malignant gastric ulcer: loss of convergence of mucosal fold, everted edge ulcer, slough present in floor of ulcer and aperistalsis around ulcer
Double contrast barium meal
- may show thickened or enlarged gastric folds, filling defect that corresponds to mass or ulcer, demonstrate failure of stomach distend normally to air and instilled barium, delayed emptying
endoscopic ultrasonography (EUS) - help in staging by identifying local stomach invasion and nodal status
Staging and evaluation of metastases
ultrasound of abdomen
- detect liver metastasis, ascites, pelvic deposits, Krukenberg tumour
liver function test
- liver metastases
CXR
- lung metastases: cannon ball lesion, pleural effusion
laparoscopy: identify macrometastases smaller than 5mm in peritoneum and liver
Surgical option of gastric ca
therapeutic endoscopy
- curative for early gastric ca or palliative for more advanced disease
endoscopic mucosal resection
- for early gastric ca that are superficial and confined to mucosa
- differentiated tumour that are slightly raised and less than 2 cm in diameter, differentiated tumour that are ulcerated and less than 1 cm in diameter
distal radical gastrectomy
- tumour in distal end-antrum
- proximal clearance: 5cm margin from growth
- distal clearance: up to gastroduodenal junction then perform Billroth I/II
(Billroth I: gastric remnant reanastomosed directly to first part of duodenum, Billroth II: duodenal stump is oversewn and continuity reestablished by gastrojejunostomy)
total gastrectomy + Roux-en-Y oesophagojejunostomy
- for tumour of cardia and proximal stomach
- remove entire stomach with distal part of abdominal oesophagus up to gastroduodenal junction with tissue of entire greater and lesser omentum and related lymph nodes
(afferent loop is detached and reanastomosed lower down to jejunum)
subtotal gastrectomy
- for tumour distally placed
- similar to total gastrectomy except proximal stomach is preserved
- then perform anastomosis of greater curve to jejunum (Billroth II)
Lymphadenectomy
- D1: removal of primary group of nodes, around 3cm of primary tumour (1-6 groups)
- D2: D1 + resection along main arterial trunks (7-11 groups)
- D3: D2 + resection of group (12-16), splenectomy, distal pancreatomy, clearance of porta hepatics, lymph node and para-aortic lymph node
After curative surgery, chemotherapy is recommended when there is involvement of lymph nodes, muscle layer or serosa.
Recently adjuvant chemo-radiation is used.
Neoadjuvant chemotherapy is used to shrink the large tumour and hence make it operable.
